Classification; Processing Of Classified Traffic - Dell PowerConnect B-FCXs Configuration Manual

Configuring Quality of Service
Table 93
they support.
TABLE 93
8802.1
Feature
802.1p Quality of Service (QoS):
•
•
•
•
802.1p priority override
802.1p marking
DiffServ support
DSCP-based QoS
QoS mappings

Classification

Quality of Service (QoS) features are used to prioritize the use of bandwidth in a switch. When QoS
features are enabled, traffic is classified as it arrives at the switch, and processed through on the
basis of configured priorities. Traffic can be dropped, prioritized for guaranteed delivery, or subject
to limited delivery options as configured by a number of different mechanisms.
This chapter describes how QoS is implemented and configured in PowerConnect devices.
Classification is the process of selecting packets on which to perform QoS, reading the QoS
information and assigning a priority to the packets. The classification process assigns a priority to
packets as they enter the switch. These priorities can be determined on the basis of information
contained within the packet or assigned to the packet as it arrives at the switch. Once a packet or
traffic flow is classified, it is mapped to a forwarding priority queue.
Packets on Dell PowerConnect devices are classified in up to eight traffic classes with values
between 0 and 7. Packets with higher priority classifications are given a precedence for forwarding.

Processing of classified traffic

The trust level in effect on an interface determines the type of QoS information the device uses for
performing QoS. The Dell PowerConnect device establishes the trust level based on the
configuration of various features and whether the traffic is switched or routed. The trust level can
be one of the following:
•
PowerConnect B-Series FCX Configuration Guide
53-1002266-01
lists the individual Dell PowerConnect switches and the Quality of Service (QoS) features
Supported QoS features
Strict Priority (SP)
Weighted Round Robin (WRR)
Combined SP and WRR
8 priority queues
Ingress port default priority
PowerConnect B-Series FCX
Yes
Yes
Yes
Yes
Yes
Yes
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